The boy we describe was 1.40 m tall, the carousel was 1.20 m in diameter, and the electrical scooter attached to it is capable of reaching a maximum speed of 40 km/h. For example, a passenger in a car travelling forward feels no acceleration, but when the car makes a turn without changing its speed the passenger will feel the ‘pull' of the radial acceleration. However, an object travelling in a circular route at a constant speed also has a constant radial acceleration, because its direction of movement is constantly changing. DiscussionĪn object travelling linearly at a constant speed has no linear acceleration. The subconjunctival hemorrhages at presentation ( a), after 5 days ( b) and complete resolution after 1 month ( c). 1a) as well as petechiae in both ear canals and on the soft palate. Additional findings of the physical examination included a mild swelling and periocular petechiae (fig. There was no limitation in ocular motility. Intraocular pressure was 12 mm Hg in both eyes, and pupillary responses were normal. The remainder of the examination was normal, with clear corneas and lenses, no intraocular hemorrhage of any kind and normal dilated fundus examination. Bilateral subconjunctival hemorrhages were noted in both eyes (fig. On examination, visual acuity was 20/20 OU. After dismounting the carousel, the boy complained of a headache, his face was swollen, both eyes were red and he was brought to the emergency room in our institution. The rapid spinning lasted for about 1 min, during which the boy suffered an intense headache, but did not lose consciousness. The boy had no control of the carousel, but fortunately an adult managed to disconnect the scooter. He had mounted a carousel that was attached to an electrical scooter, and had spun round on it very rapidly. Case ReportĪ healthy, 10-year-old boy was examined in our institution due to bilateral diffuse subconjunctival hemorrhage. The physics and pathophysiology of this unusual pathogenic mechanism are reviewed. We report a patient who suffered ocular injury caused by radial acceleration on a carousel. Acceleration forces causing ocular trauma have also been described in bungee jumps and rollercoaster rides. Typical ocular findings in this entity include retinal hemorrhages and retinoschisis, the pathogenesis of which is attributed to acceleration-deceleration forces and increased intracranial intravascular pressure. The most demonstrative example for severe ocular trauma by this mechanism is the ‘Shaken Baby syndrome'. However, acceleration forces also constitute a possible mechanism of ocular injury, which may cause significant damage without any direct contact with the eye. Ocular trauma is usually categorized into direct mechanical and indirect trauma.

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